Mental workouts, unlike physical exercise, do not demand significantly more energy than usual even if people’s belief that they have drained their brains might be enough to induce weariness, according to Scientific American.

Temporary mental exhaustion is a genuine and common phenomenon, which differs from chronic mental fatigue associated with regular sleep deprivation and some medical disorders. Everyday mental weariness makes sense, intuitively, said the magazine.

Complex thought and intense concentration require more energy than routine mental processes, and just as vigorous exercise tires our bodies, intellectual exertion should drain the brain. What the latest science reveals, however, is that the popular notion of mental exhaustion is too simplistic.

According to Scientific American’s article, the brain continuously slurps up huge amounts of energy for an organ of its size, regardless of whether people are tackling integral calculus or clicking through the week’s top 10 LOLcats.

Although firing neurons summon extra blood, oxygen and glucose, any local increases in energy consumption are tiny compared with the brain’s gluttonous baseline intake.